added lesson on sapply
added lesson on sapply

NEONScience/NEON-Data-Skills,NEONScience/NEON-Data-Skills,NEONScience/NEON-Data-Skills,NEONScience/NEON-Data-Skills,mjones01/NEON-Data-Skills,mjones01/NEON-Data-Skills,mjones01/NEON-Data-Skills